I have a sentry safe model A4887 with an electronic comb w/ key. We have the correct combo but the door will not open. The batteries are brand new. How do I get the door open?

Try changing the batteries first. No the electronic combo would not be erased unless someone previously changed the combination. There is probably something causing the bolts to not retract. The lock may fail if there is any pressure on the bolts and or the door of the safe. Hopefully this information helps.

for security reason ....only company can reset code.

Sounds like the batteries are dead.
How to install sentry safe batteries
slide open the battery cover located just below the keypad.
Insert a paper clip or pen point into the small hole in the cover. Push in while sliding cover to the right. Disconnect and remove the battery holder. Insert the 4-batteries as indicated.
reconnect the connector and put back the battery holder. Slide the cover back in place.
How do I insert the batteries on my advanced electronic lock safe? On the newer model Fireproof Sentry Safes my locksmith recommended me To install batteries,
turn the electronic lock case to the right and remove. Insert four new batteries as indicated, replace the electronic lock case and turn to the left to reassemble.

Locksmiths say this is how to install sentry safe batteries
slide open the battery cover located just below the keypad.
Insert a paper clip or pen point into the small hole in the cover. Push in while sliding cover to the right. Disconnect and remove the battery holder. Insert the 4-batteries as indicated.
reconnect the connector and put back the battery holder. Slide the cover back in place.
How do I insert the batteries on my advanced electronic lock safe? On the newer model Fireproof Sentry Safes my locksmith recommended me To install batteries,
turn the electronic lock case to the right and remove. Insert four new batteries as indicated, replace the electronic lock case and turn to the left to reassemble.

You can do a Key override
If your electronic lock fails or you do not have any codes
available, you may use a key override to access this unit.
1. Remove the battery cover, disconnect and remove the
battery holder.
2. Insert the skeleton key (second set of keys provided)
into the key hole inside the opening for the battery.
3. Turn the key to the right.
4. Turn the four-bitted key to the right.
5. Open the door.

You can download the user manual here:
http://www.sentrysafe.com/pdfs/OwnersManuals/172967.pdf

Key override
If your electronic lock fails or you do not have any codes
available, you may use a key override to access this unit.
1. Remove the battery cover, disconnect and remove the
battery holder.
2. Insert the skeleton key (second set of keys provided)
into the key hole inside the opening for the battery.
3. Turn the key to the right.
4. Turn the four-bitted key to the right.
5. Open the door.

You can download the user manual here:
http://www.sentrysafe.com/pdfs/OwnersManuals/172967.pdf

I have a different model but I had the same problem. Called customer service and they had me push up on the handle and enter the code. That didn't work but then they had me tap the safe with a rubber mallet 5 times above the panel and 5 times to the right of the panel. That worked for me. Hope one of those works.

A locksmith would tell that you have to enter the combo again in order to retract the bolts so the door will shut.

Hello,

I am a Safe Specialist i have been reading some of your problems and this should help there is no code if you have lost yours only the default code for the model 1610 the default code is: 77,22,09,11,64 try that if you havent changed it and with this problem with people not getting the handle open with the green light happening i suspect this is a issue with the lock mechanism i have had many of the same problems with people bringing them in when you get you safe open it and where the lock is put some lubricate on the lock regulary as the lock sticks and wont open if you havent done this then you cannot get it open see you local safe specialist and tell them what i have said and they may or may not be able to get your safe open i hope this has helped Rob Safe Specialist World.

This manual will answer both of your questions.
http://www.sentrysafe.com/pdfs/OwnersManuals/501664.pdf